1. Technical Field
The present invention relates to a zoom lens and an image capture apparatus. In particular, the invention relates to, for example, a zoom lens, which is suitable for a digital still camera, a digital video camera, a surveillance camera, or the like while having a high zoom magnification power and being able to achieve an increase in imaging field angle sufficiently, and an image capture apparatus using the zoom lens.
2. Description of the Related Art
Recently, as the digital still camera market has become very large, users have varied demands for digital still cameras. To say nothing of an increase in image quality, a decrease in size, and a decrease in thickness, demand for an increase in the magnification of the image taking lens and an increase in the angle of view has also become very strong.
Generally, there is a negative lead type zoom lens of which a lens group closest to the object side has a negative refractive power. Since it is easy for the negative lead type zoom lens to decrease a diameter of a front lens, it is advantageous in reduction of size. Hence, the negative lead type zoom lens has been widely used as a type suitable for increasing the angle of view.
Further, in image capture apparatuses using the solid-state image pickup device, it is preferable to use a zoom lens which is telecentric on the image side in that the zoom lens is able to make image field intensity uniform. In such a zoom lens, it is preferable that the lens group closest to the image side should have a positive refractive power.
As a zoom lens which is a negative lead type and of which the lens group closest to the image side has a positive refractive power, there has been proposed a four group zoom lens which includes four lens groups of negative, positive, negative, and positive refractive powers arranged in order from the object side to the image side (for example, refer to Japanese Unexamined Patent Application Publication No. 2008-191385).
On the other hand, as a negative lead type zoom lens, there has also been proposed a small zoom lens which includes three lens groups of negative, positive, and positive refractive powers arranged in order from the object side to the image side (for example, refer to Japanese Unexamined Patent Application Publication No. 2006-78581).